# Relationship history for MSHA mine 1401127

Current hierarchy: **Christopher Mark  Johnson → CMJ Enterprises LLC d/b/a  Johnson Sand → Johnson Sand**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Knox Sand Company → Johnson Sand; 1950-01-01 to 1985-06-30; source msha-controller-operator-history
- **controller_controls_mine:** Darwin  Knox → Johnson Sand; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Darwin  Knox → Knox Sand Company; 1950-01-01 to 1985-06-30; source msha-controller-operator-history
- **operator_operates_mine:** Johnson Sand → Johnson Sand; 1985-07-01 to 2021-02-28; source msha-controller-operator-history
- **controller_controls_mine:** Pamela M  Johnson et al → Johnson Sand; 1985-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Pamela M  Johnson et al → Johnson Sand; 1985-07-01 to 2021-02-28; source msha-controller-operator-history
- **controller_controls_operator:** Gary L  Johnson et al → Johnson Sand; 1985-07-01 to 2021-02-28; source msha-controller-operator-history
- **operator_operates_mine:** Johnson Sand → Johnson Sand; 2021-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Christopher Mark  Johnson → Johnson Sand; 2021-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Christopher Mark  Johnson → Johnson Sand; 2021-03-01 to current/open; source msha-controller-operator-history